Analysis of the thickness and vascular layers of the choroid in eyes with geographic atrophy using spectral-domain optical coherence tomography

PURPOSE: To analyze the total choroidal thickness and thickness of the individual vascular layers of the choroid in eyes with geographic atrophy (GA), using spectral-domain optical coherence tomography. METHODS: A cross-sectional retrospective review identified 17 patients with GA (17 eyes) and 14 age-matched healthy subjects (14 eyes), who underwent high-definition raster scanning at New England Eye Center, Boston, MA. Patients were diagnosed with GA based on clinical examination and investigations. Two independent raters evaluated the thickness and vascular layers of the choroid. RESULTS: Mean choroidal thickness was significantly lower in eyes with GA when compared with age-matched healthy eyes (P < 0.0001). Subfoveal choroidal thickness in eyes with GA was significantly less when compared with healthy eyes (158.1 ± 23.65 μm versus 267.5 ± 19.27 μm, P = 0.001). Subfoveal large choroidal vessel layer thickness and medium choroidal vessel layer/choriocapillaris layer thickness were significantly reduced in eyes with GA when compared with healthy eyes (P = 0.001 and P < 0.0001, respectively). CONCLUSION: The choroid is significantly thinner in eyes with GA involving the fovea when compared with healthy eyes. Choroidal thinning in GA involves all its vascular layers. Further studies involving prospective correlation of choroidal vascular changes to the quantitative progression of GA is expected to provide further insight on the choroidal angiopathy associated with GA.